Synthesis of phenyl-substituted 2H, 5H-pyrano[4, 3-b]pyran-5-ones and related heterocycles and via a domino knoevenagel condensation/6π-Electron electrocyclization of 4-Hydroxy-6-phenyl-2H-pyran-2-one with cyclic and acyclic α, β-unsaturated aldehydes under different conditions
A range of new 7-phenyl-2H, 5H-pyrano[4, 3-b]pyran-5-ones and related tricyclic heterocycles was prepared in a single step by means of a domino Knoevenagel condensation/6π-electron electrocyclization under different reaction conditions, including thermal and microwave conditions. The influence of several ionic liquids as solvents was also studied. 2009 Verlag der Zeitschrift fuer Naturforschung, Tuebingen.